Why you should never drive through floodwater

driving with floods NRMA
Don't drive through flood water

During sustained periods of wet weather, one of the key safety messages is simple: don’t drive through floodwaters. Doing so will likely severely damage your vehicle and could also put your life at risk.

The temptation is understandable – it’s been a tough drive and you’re within minutes of the comforts of home when you’re confronted with what looks like a relatively shallow and steady flow of water across the road.

As the SES will tell you, still waters can run deep and the flow in front of you could pack a punch of a tonne per metric metre, which can tear away the road surface and result in a much deeper gully than is apparent.

A typical car will lose power in depths greater than 15cm as water enters the exhaust and washes into the air intake, causing it to float once flood levels exceed 30cm.

Modern cars with electrically powered windows and locks are almost impossible to escape from once water finds its way into wiring and motors, disabling switchgear and pressing on bodywork.

Owners of off-road vehicles shouldn’t assume they are immune, as the fast-flowing force can overcome four-wheel drive or any other tool at their disposal.
Even if you have the good fortune to survive getting caught in a flood in your car, the damage your vehicle will certainly suffer will make you regret taking the chance.

And if you get caught in floodwaters, NRMA Roadside Assistance can't help you: not only from a safety perspective but also because damage to your vehicle suffered in this scenario becomes an insurance issue.

We have also described the potential damage to vehicles here but the threat to life should be a good enough motivation: the US Centres for Disease Control and Prevention report that almost half of all flood-related drownings occur when a vehicle is driven into water, far ahead of pedestrian deaths.